The incidence of acute renal failure (ARF) after cardiac surgery varies from 1-30% depending on the definition. The risk factors leading to ARF after cardiac surgery have been well characterized. In patients with normal preoperative renal function, risk factors associated with the development of ARF include advanced age, female gender, diabetes, peripheral vascular disease, congestive heart failure, hypertension, prior coronary artery bypass grafting (CABG), preoperative intraaortic balloon pump (IABP) use, and a high white blood cell count.
After coronary revascularization, patients who develop ARF experience significant increases in both short- and long-term mortality. Mortality is far lower in patients with normal renal function (0.9 %) then in patients with accute renal failure (up to 60%).
Nonpulsatile flow and hypotension lead to renal vasoconstriction and decreased RBF. Norepinephrine and renin increase. High renin correlates c renal failure. Thromboxane from platelets also cause vasoconstriction. 2% of CPB patients will have ARF, if ARF occurs mortality is 60-80%. In normal kidney patients pulsatile vs non-pulsatile flow does not change ARF incidence. Pulsatile flow may be better for patients c CRI. ARF after CPB is more related to cardiac function after surgery than with mean pressures (even <50) while on CPB.
Risk factors for ARF following CPB include starting Cr 1.9 or higher, and combined/complex surgery.
Dopamine does not improve renal outcome post CPB, and it may be harmful by increasing arrhythmias post-op. A metaanalysis of 13 RCTs including 1,059 patients suggested that fenoldopam (a D1 agonist) may reduce the risk of in-hospital death (OR 0.46, p = 0.002) and renal replacement therapy (OR 0.36, p < 0.001) as well as reducing ICU LOS by 0.93 days (p = 0.002).
Summary of Renal Dysfunction in CPB
- 2% incidence (60-80% mortality when it occurs)
- Risk factors include starting Cr 1.9 or higher, combined/complex surgery
- Consider pulsatile flow for patients who already have CRI
- Fenoldopam (but not dopamine) may reduce death, renal replacement therapy, and ICU stay.
J. Cardiothorac. Vasc. Anesth.: 2008, 22(1);27-33
Brown et al. Multivariable prediction of renal insufficiency developing after cardiac surgery. Circulation: 2007, 116(11 Suppl);I139-43